docs: def _get_stddevs(self, C, rup, dists, sites, stddev_types):
          """
          Returns the aleatory uncertainty terms described in equations (13) to
          (17)
          """
          stddevs = []
          num_sites = len(sites.vs30)
          tau = self._get_inter_event_tau(C, rup.mag, num_sites)
          phi = self._get_intra_event_phi(C,
                                          rup.mag,
                                          dists.rjb,
                                          sites.vs30,
                                          num_sites)
          for stddev_type in stddev_types:
              assert stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES
              if stddev_type == const.StdDev.TOTAL:
                  stddevs.append(np.sqrt((tau ** 2.0) + (phi ** 2.0)))
              elif stddev_type == const.StdDev.INTRA_EVENT:
                  stddevs.append(phi)
              elif stddev_type == const.StdDev.INTER_EVENT:
                  stddevs.append(tau)
          return stddevs